Maple syrup production involves drilling holes into (i.e., “tapping”) maple trees, collecting the sap that exudes from the wound, and then reducing or “sugaring” down the sap using reverse osmosis and evaporators to form the final syrup. Details of maple syrup production are described in the publication entitled “North American Maple Syrup Producers Manual” (second edition), produced by Ohio State University, in cooperation with the North American Maple Syrup Council, and edited by Heiligmann, Koelling and Perkins, which is incorporated by reference herein by way of background information.
The traditional way of collecting maple sap uses buckets at the tap source. The sap is then collected in a tank and then transported to the “sugarhouse” for processing. Over the years, a variety of specialized hardware has been developed for this task, including both sap spouts and specialized sap collection buckets or bags. For many years, however, the basic techniques of maple syrup and sugar production remained essentially unchanged.
More recently, modern syrup producers have replaced the traditional bucket collection system with a tubing system that includes special spouts (usually 5/16″ outside diameter (OD) or 7/16″ OD diameter) and plastic tubing “droplines” (usually 5/16″ ID diameter and about 18″ to 36″ in length) connected to the various spouts. The droplines are then connected to lateral lines (also usually formed from 5/16″ ID diameter plastic tubing) that run between different maple trees. The lateral lines are in turn connected to one or more “main lines” (usually ¾″ to 2″ diameter) that run to the sugar house. Such systems are described in, for example, U.S. Pat. Nos. 2,877,601, 2,944,369, 3,046,698, and 3,057,115, and may either be gravity fed or utilize a vacuum pump to move the sap to a central collection point (e.g., an evaporator in the sugarhouse).
The sap flows from the tree through the spout and then through the line system when the pressure within the tree is greater than that in the lines. The line system eventually conveys the sap to the evaporator. To facilitate the extraction and transportation of the sap from the tree and to the evaporator, some systems use a pump to pull a vacuum within the line system. This increases the pressure differential between the inside of the line system and the tree, thereby increasing the volume of sap flow as compared to that which would naturally occur by gravity.
FIG. 1 is a schematic diagram that illustrates a portion of a dual-line system that includes a top mainline 230A suspended slightly above a bottom mainline 230B. At intervals along the dual mainlines, a manifold 231 connects the top and bottom mainlines lines to a third main line 230C that has individual lateral lines 220. Spouts (not shown) are connected to the lateral lines 220 via drop lines 210. While this dual-line system generally improves sap yield, the dual-line portion runs from the vacuum pump system and terminates in the main line portion of the system, which limits its effectiveness.